The invention relates to a double roll machine such as, for example, a roll press which comprises two rotatably seated rollers that are rotatable in opposite directions and are connected to a rotary drive.
Roll presses or roller mills comprise two rotatably seated rollers rotating in opposite directions that form a nip between them in which granular solid material is subjected to a pressure stressing. The four roller bearings are integrated in rectangular pillow blocks that respectively rest on a guideway of the lower part of the machine frame. One of the two rollers is usually constructed as a fixed roller that is directly supported against an end wall of the machine frame, whereas the other roller is constructed as a movable roller and is supported against the hydraulic cylinder of a hydro-pneumatic system by two blocks. The pressing power of the roller being exerted and the adjustment of the width of the nip are undertaken with this hydro-pneumatic system.
In a known roll press of this species (brochure "Rollenpresse" No. 11-304d of KHD Humboldt Wedag AG), the two rollers each comprise a driving journal projecting out of the machine frame, and a slip-on gearing constructed as a planetary gearing is slipped onto the two driving journals lying diagonally opposite one another. An electric motor that transmits its torque onto the respective slip-on gearing using V-belts for a rotary drive of the respective roller is situated on the upper side of the slip-on gearing. Every roller is thus driven by one electric motor and a total of two drive motors are present in the roller press. This drive arrangement for the roller press can be technically suitable up to a drive power of about 500 kW per motor. Given a requirement for even higher drive powers, the known drive arrangement can present problems insofar as the motors become so large that they can no longer be accommodated in the space above the slip-on gearings and because the V-belt forces that occur and that can deteriorate, the motor bearing requires an intermediate gear that cannot be built on the slip-on gearings because of its volume and weight.
An object of the invention is to create a double roll machine such as, for example, a roll press or roller mill that is suitable for high throughput powers and high roller pressing powers as well as for high drive power requirements without having to have recourse to drive motors comprising an intermediate gear.
A further object of the invention is to provide an improved method and apparatus for the continuous pressure comminution of brittle grinding stock utilizing the principles of grain comminution and product bed comminution in the same roller press and improving the operation of the press in accordance with these principles by a unique drive arrangement.